The constantly increasing complexity and duration of surgical intervention, comorbidity that leads to severe circulatory and respiratory disorders, multifactoriness of functional and metabolic disorders--this also needs a rapid and accurate assessment of patients and objective monitoring. The value of monitoring is determined by the results of timely diagnosis of disorders and the prevention of severe complications, including circulatory arrest, regional and global systolic function of the ventricles, which undoubtedly assists in choosing the tactic of intensive care. Intracardiac echocardiography makes it possible to record changes in cardiac cavity volume in real time, to calculate ejection fraction as the major pump coefficient, which is of prime importance in the surgical correction of coronary circulation with one-stage correction of mitral insufficiency. Imaging of cardiac cavities, evaluation of valve apparatus function, timely diagnosis of myocardial contractility, by detecting the areas of a pathological condition, are main criteria for undertaking medical measures and choosing a treatment policy.